1. Field of the Invention
This invention relates to sensors for use in measuring an analyte or analytes in a gaseous sample.
2. General Background
Analysis of a subject's exhaled breath is a promising clinical tool, with potential application in the diagnosis and treatment of many conditions. For instance, changes in nitric oxide (NO) concentration in exhaled breath can indicate a change in the level of inflammation in the airway of an asthmatic, indicating an increase in the likelihood of an asthmatic attack. Excessive carbon monoxide (CO) can indicate hemolytic jaundice, and high levels of hydrogen can indicate carbohydrate malabsorption. Additionally, breath analysis can be used by law enforcement officials and others to test for the concentration of alcohol in a subjects breath.
It would be especially desirable if patients could conduct their own breath analysis, at home, work, or school. If they could do so, breath analysis could be used to manage chronic diseases such as asthma. Indeed, some of the present inventors have developed both a device (U.S. Ser. No. 10/334,625) for quantifying breath analytes, and a method for managing asthma by monitoring NO levels (U.S. Ser. No. 10/659,408). The disclosures of these applications are incorporated herein by reference as if set out in full.
A necessary part of any portable breath analysis system is the sensor that responds in some way to the analyte in the subject's breath. For a variety of reasons, sensors that are appropriate for a portable system are not re-usable or may require calibration or user intervention to function adequately. There are a variety of large laboratory-based instruments available, but they are generally cumbersome, expensive and difficult to maintain. Therefore, there is a need for a true disposable or calibration-free multi-use system.